The Stanley Cup playoffs were a demonstration of the changing of the fourth line in the NHL.

The champion Kings featured Mike Richards and Trevor Lewis, two one-time first-round picks, on their bottom line. The Rangers usually had Dominic Moore and Brian Boyle, who Monday said he's looking for bigger opportunities as a free agent this summer.

The teams they knocked out a round prior, the Canadiens and Blackhawks, rocked even more distinctive No. 4 trios. Montreal's unit of Brandon Prust, Daniel Briere and Dale Weise left the Bruins needing Advil with their clutch goals, and Chicago sets the bar for skilled and speedy fourth lines, featuring Marcus Kruger and Ben Smith.

It's the new template for fourth lines — fast, skilled, productive. The New NHL, brought on by the removal of the red line and calling of more holding and interference penalties in 2005, is taking on one of the final holdover of the old days — the traditional fourth-liners.

These are the guys who won't score more than five goals a season, but become fan favorites by providing energy and sticking up for their teammates. They crash, they bang, they skate with purpose, they play selflessly by blocking shots and sacrifice their bodies by unloading on opponents.

That was how the Bruins built their fourth line the past four years. The group of Daniel Paille, Gregory Campbell and Shawn Thornton was highly effective in its Merlot prime, a significant reason the Bruins uncorked champagne in Vancouver three seasons ago.

Yet in this past playoff season, they looked dried up. Prust, Briere and Weise set the tone for the Habs with big goals; Paille, Campbell and Thornton — reunited in Game 4 of that series — chased the puck.

So it came as no surprise when Thornton was given a handshake and shown the door Monday after seven seasons of hard work. Not to oversimplify his contributions, which came in many areas on and off the ice, but the best statistical grasp of Thornton's tenure were the 110 times he dropped the gloves in a Spoked-B uniform.

It's doubtful any player will fight 110 times for the Bruins over the next seven seasons. Line brawls are ancient history. New players are required to wear visors. Concussion awareness is at an all-time high.

“I'm sure it's a slow trend, trying to phase it out a little bit,” Thornton said of fighting back in September. “It's been going down that road for the last couple years. We'll see what happens.”

“There’s trends in hockey and the fisticuffs trend — again, this doesn’t characterize Thorty as just a fighter because he contributed on that line, and that line has had a lot of success in the past — but there is definitely, we’re trending away from that style,” general manager Peter Chiarelli said last month.

By the eye test and advanced analysis, Thornton was the Bruins' worst forward last season. He was used against the lowest quality of competition and in the lowest-risk situations. Thornton was a skilled enforcer, but a smart elephant is still not as wise as a human.

In the modern NHL, all 12 forwards need to skate and play. You put yourself at a disadvantage, especially in the postseason, by playing with brawlers.

Chiarelli will take the Bruins out of the caveman era and into modern times by remodeling the fourth line. If he stays in-house, the general manager can replace Thornton with Craig Cunningham, Justin Florek, Seth Griffith and Matt Lindblad.

Perhaps even natural centers Alexander Khokhlachev and Ryan Spooner, Providence's top two scorers in the playoffs, could get looks on the line, either pushing Campbell at center or getting switched to wing. All those options are fast, skilled players who can maintain a high tempo.

“Their interests should be highly pushed,” assistant general manager Don Sweeney said last week of Khokhlachev and Spooner. “We've moved players around [to the wing] — Chris Kelly, Carl Soderberg, Tyler Seguin, they'e all played the wing. We want [Khokhlachev and Spooner] to push those players with higher skill-set. Ryan is a high-end skater. Alex has improved there. Playing against bigger, stronger players is the next challenge.”

One faster player does not a philosophy change; as long as Cam Neely is still in an executive chair, the Bruins' team identity won't be getting lost in the laundry. They're still big and strong and physical and defensive-oriented. They will not play like the Canadiens or the Rangers.

They just can become a little faster and skilled now. Out of the caveman era and into the digital revolution.